Process for recovering oil from the solvent cleaning or scouring of raw wool or woolfabric



Aug. 19, 1952 DERBY 2,607,786

PROCESS FOR RECOVERING OIL FROM THE SOLVENT CLEANING 0R SCOURING OFRAVLWOOL 0R WOOL FABRIC Filed Nov. 30-. 1948 4 Sheets-Sheet 1 aozandzztflemfi byMSMW K F Aug. 19, 1952 R. E. DERBY 2,607,786 PROCESS FOR RECOVERING OIL FROM THE SOLVENT CLEANING 0R SCOURING 0F RAW WOOL 0R WOOL FABRIC Filed Nov. '50, 1948 4 Sheds-Sheet 2 Aug. 19, 1952 Filed NOV. 30, 1948 R. E. DERBY PROCESS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING 0F RAW WOOL OR WOOL FABRIC 4 Sheets-Sheet .3

2 9 1km: swim/w flifiowneyg Aug. 19, 1952 R. E. DERBY 2,607,786

PROCESS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OR WOOL FABRIC Filed Nov. 30, 194 4 Sheets-Sheet 4 Moron 8 i U 1220832302 WEJMZ:

Patented Aug. 19, 1952 PROCESS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OBI-WOOL FABRIC Roland E. llerby, Lowell, Mass. Application November 30,1948, Serial No. 62,736

The object of thisinvention is to effect the recovery of usable oil from the liquid resulting from the solvent cleaning or scouring of raw wool or wool-fabric.

In the treatment of wool in the various oper- .ations in the textile art, as for exampleinv the carding. spinning and weaving processes,.it is common to apply oil as a lubricant particularly to create a satisfactory slip between the fibers. The wool fiber itself also contains a certain amount of oil, grease or lanolin. Any oil thus present for these or-any other reasons in raw wool or wool fiber is extracted. therefromin any solvent cleaning or scouring process, and its .recovery from'the liquid resulting from any such process is of substantial commercial importance because in particular such voil when recovered may be re-used as a lubricant for 001 or for other purposes.

The object of the present invention is to recover such an oil freed from dirt and any component of fat derivatives which would otherwise render the recovered oil thick, gummy and unsatisfactory. v

The present invention provides a novel and emcient process for thus recovering in a commercially pure state such oil.

The solvent cleaning operation may be performed either as a batch process or as a continuous process, and by the use of any suitable solvent, and the invention in its broader aspects is applicable to either of these processes regardless of the particular solvent employed. The continuous solvent cleaning operation of wool has been successfully developed in accordance with the invention disclosed in Letters Patent No. 2,176,705, granted October 17, 1939, and, the solvent there employed vis preferably ofthe chlorinated hydrocarbon group because of the non-inflammable and non-toxic character of such a solvent, and this is the most satisfactory, efiicient and safe method particularly when large quantities of fabric or wool are to be handled. But at the other extreme, the wool may be solvent cleaned or scoured, whether in the form of fiber or partially or wholly manufactured, by the batch process and by the use of the common inflammable solvents such as naphtha, when the danger from fire can be.

avoided or risked.

The basic principle of the invention in its broader aspects resides in mixing with the liquid resulting from the solvent cleaning process an alkaline agent compatible with the solvent in a tank. This effects partial saponification of the '4' Claims." (01. zoo-412.5)

fats contained in the liquid and coagulates the dirt and fatty matters causing the formation of a coagulant mass which floats to the top of the tank and carries with it the bulk of the dirt in the liquid. At the same time any heavier dirt which has been held in suspension in the liquid but which does not appear to contain fats,v sinks to the bottom of the tank in the form of a sludge. The liquid thus freed from the coagulant mass which has floated to the top and from the sludge which has sunk to the bottom, and which now is chiefly composed of the solvent andthe oil which it is desired to recover, is now decanted to a suitable still in which the solvent .is distilled from the decanted liquid thus leaving the oil substantially free from dirt to be drawn off from the still while the solvent passes to a suitable condenser-and is there recovered.

The basic principles of the invention are thus the same whether the process and the apparatus employed is either of the batch or continuous type.

The nature and objects of the invention will appear more fully from the accompanying description and drawings and will be particularly pointed out in the claims.

The drawings illustrate in Figs. 1 to 5 inclusive an apparatus for carrying out the method or process of the invention when the operation is continuous, while in Fig. 6 is illustrated a simple and preferred form where the operation is of the batch type.

The apparatus illustrated in Figs. 1 to 5 inclusive is particularly designed to be embodied in an apparatus such as is illustrated in the aforesaid Letters Patent No. 2,176,705.

In the Figs. 1 to 5 of the drawings,

Fig. 1 is a front elevation of the apparatus partially broken away and somewhat diagrammatical,

Fig. 2 is a rear elevation of the tank, I r

Fig. 3 is a right hand elevation of the tank,

Fig. 4 is a-front elevation and Fig. 5 is an end elevation of an auxiliary still. I

. Fig. 6 illustrates the batchoperation and is a side elevation of the principal features of the entire apparatus also somewhat diagrammatic.

Referring to the aforesaid Letters Patent No. 2,176,705, the liquid resulting from a continuous drying operation continuously discharges from a chamber ll indicated in Fig. 1 through a suitable filter or strainer and thence through a pipe indicated at "and I3 respectively, and it is this liquid from which the oil is to be recovered.

In the construction illustrated in Fig. 1, a

alkaline agent with the liquid in the tank.

' l8 separated "by suitable partitions and having V-shaped bottoms IE sloping'to'ward the rear.

The first section I4 has an admission port 23 near the bottom and a discharge port 2| near the top. The last section 18' has the discharge port 22 near the top and the intermediate sec tions such as I5, I B and I! connect in sequence with each other and with the last section It through ports 23 midway the top and bottom. Suitable baliie plates 24 are also provided to divertthe liquid discharged from one tank into the next toward the bottom and a bafile25 prevents direct discharge through the port 22.. I

Suitable means are provided for mixing the In the construction illustrated the alkaline agent in liquid form is carried in a reservoir 2.5 and discharged therefrom into the pipe I3 thence into the tank section I4 in a continuous flow under the control of the valve 21. A stirrer 23, see Figs. 2 and 3, driven by. a motor or other suitable means acts to effect a thorough mixture of the liquid discharging from the tank 'll and the alkaline agent discharging from the reservoir 26. V 1 v v In the preferred continuous dry cleaning process, one of the chlorinated hydrocarbon group of solvents and particularly trichlorethylene or perchlorethylene is employed asmost satisfactory because of its non-inflammable and non-toxic characteristics and eihcient action. .The alkaline agent to be mixed with such a solvent in carrying out the present invention is preferably an alkaline liquid substantially anhydrous, nonsoluble in, and of lower specific gravity than such solvent and for that purpose triethanolamine has been found best to efiect the required saponification. The determination of the alkaline agent compatible with the solvent employed will however depend upon well. known factors. Any alkaline agent will cause some saponification and with somedegree of efficiency. Even water solutions of solid alkaline agents such as borax and soda ash are theoretically usable, but they separate rapidly in the liquid resulting from the solvent; cleaning. process and thus reduce efiiciency. Furthermore in the case of the chlorinated hydrocarbon solvents, the presence of the amount of water necessary to carry in solution the solid alkaline agents causes a small amount of hydrolysis of the solvent andalso some solution of the solvent in water which is undesirable. The matter of cost is alsolargely determinative as between thevalue of the 'solvent lost on the one hand, and the greater cost of an alkaline agent such as triethanolamine over borax or soda ash. 7 v V The result of mixing the alkalinejagent with the liquid obtained from the solvent cleaning operation is to effect a partial saponification of the fats contained in the liquid and coagulate the dirt and fatty matter causing a coagulated mass toform and float to the top of the tank. Since the mixing'is continuously going on in the first section 14, little if any coagulation takes place therein but rapidly occurs in the succeeding sections. It is believed that the floating of this 4 coagulant mass to the top is assisted by the use of an alkaline agent which itself is of lighter specific gravity than the solvent and that separation is effected more efficiently due to such lighter specific gravity. At the same time there is a slight separation of heavier dirt which has been held in suspension and which does not appear to contain fats, and this settles to the bottom of thetank sections in the form. of sludge.

The liquid in the tank thus freed from the coagulant mass at the top and the sludge deposited at the bottom is decanted from the tank through. the pipe 29 into the still 3B. There 'isusually little coagulant in the last section I8 and this is prevented from passing out through .thepipe29 by the baiile 25. This still may be of any suitable construction and is preferably the same as that illustrated in the aforesaid patent where by means of a steam heated coil 3| the solvent is distilled off, passed through the pipe 32 to a suitable condenser 33 and is there recovered. This leaves at the bottom of the still the oil; freed from dirt and commercially purified and suitable for lubricating and other purposes, which may be drawn off through the drain 34.

When the continuous operation is stopped, or whenever it may be desired, the entire liquid freed from the coagulant mass and sludge is decanted into the still for the recovery of the solvent and oil, and for this purpose there is provided a pipe 35 opening through valves 35 into the tank sections near the bottom above the sludge and these valves are opened until the floating coagulant mass is lowered to just above the valves. v,

'From time to time as the coagulant mass at thetop and the sludge at the bottom accummulate, it is necessary to draw these materials off from the tank and preferably to recover therefrom the solvent therein. For this purpose an auxiliary still 31, shown more in detail in Figs. 4 and 5, is located below the level of the tank and provided with a jacket 38 heated from the steam pipe 39. A pipe 40 provided with sections" 4| opens into the several tank sections where the coagulant mass is formed at points somewhat below the discharge port 22. Each of these sections is preferably provided. with sight glasses 42 and valves 43 and thus, when through the sight glasses the undesirable accumulation of the coagulant mass has been reached, the valves are opened, and the. coagulant mass drained off into the auxiliary still 31. Another pipe HI connected to the still is also provided with sections opening to the bottom of the tank sections and each controlled by a Valve 45 so that by opening these valves the sludge accumulated at the bottom may also be drained 011 into the auxiliary still 31. Then by operating the auxiliary still, the solvent contained in the coagulant mass and sludge is distilled off and passes through the pipe 46 into the condenser 23 where it is there recovered. The auxiliary still is provided at the front with 'a removable door 47 enabling the waste mass remaining after the solvent is distilled off to be removed. This usually is of norvalue and is thrown away.

The invention in its broader aspects, as already pointed out, is equally applicable to a process for recovering the oil and also the solvent when the batch process of the' dry cleaning or scouring, as for example of raw wool, is employed. An apparatus for carrying out this embodiment of the invention is illustrated in a simple and more or less diagrammatic form in Fig. 6.

As here illustrated a batch, as for example of raw wool, is submitted to the solvent cleaning process in the tank 59. When the dry cleaning operation has been concluded, the valve 51- is opened and the liquid resulting from the dry cleaning operation is drained off through the pipe 52 into the tank 53 corresponding in general to the first section M of the tank previousiy described. This tank opens near the bottom through a pipe 54 having the valve 55 into a still 56 which may be similar to the still 30. The tank 53 also opens at the bottom through a pipe 51 having a valve 58 into an auxiliary still .59 which also may be similar in construction to the still 31. Similarly a condenser 60 is provided into which through a pipe 6| solvent distilled off by the still 56 and through a pipe 62 solvent distilled off from the still 59 passes to the condenser.

The reservoir 63 contains the alkaline agent fed under the control of the valve 64 through the pipe 65 to the pipe 52.

The tank 53 is provided with the mixing stirrer 6'6 driven by suitable means such as a motor similar to that already described.

The liquid resulting from the solvent cleaning operation is thus mixed with the alkaline agent by the stirrer in the tank 53. The operation of the stirrer is then stopped and, the saponification taking place as previously described, results in a coagulant mass which rises to the top in the tank 53 at 61 carrying with it the dirt. The valve 55 is then opened decanting off from the tank 53 the resultant liquid freed from the coagulant mass which floats on the top and from the sludge 68 which has settled to the bottom. The valve 55 is closed when the coagulant mass has been lowered, as at 69, to near the level of the pipe 54. The coagulant freed liquid decanted off into the still 56 is then subjected to the distilling operation, recovering the solvent in the condenser 60, and the desired oil is withdrawn at as before.

The coagulant mass 69 and the sludge 6B are then drained off through the pipe 51 into the auxiliary still 59, the solvent recovered from this material and the waste material withdrawn as before. The term cleaning and scouring as herein employed is to be understood as applying to either or to any similar treatment in which an organic solvent is employed. The term wool is to include either raw W001, W001 fibre, wool fabric or material made from or containing wool.

The apparatus disclosed herein is made the subject of a divisional application, Serial No. 283,544, filed April 22, 1952.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. The process of recovering oil and solvent from the liquid obtained from the cleaning and scouring of wool with a volatile chlorinated hydrocarbon solvent which consists in mixing the said obtained liquid with its contained oil, fatty matter and dirt and an alkaline liquid substantially anhydrous, non-soluble in, and of lower specific gravity than the solvent in a tank to effect partial saponification of the fats contained in the liquid and to coagulate the dirt and fatty matter, and, after the coagulant mass thus formed has floated to the top carrying with it the bulk of the dirt in the liquid, decanting the resulting coagulant freed liquid from the tank, and distilling the solvent from the decanted liquid to leave an oil substantially free from dirt.

2. The process of recovering oil and solvent from the liquid obtained from the cleaning and I scouring of wool with a solvent of the group consisting of trichlorethylene and perchlorethylene which consists in mixing the said obtained liquid with its contained oil, fatty matter and dirt and triethanolamine in a tank to effect partial saponification of the fats contained in the liquid and to coagulate the dirt and fatty matter, and, after the coagulant mass thus formed has floated to the top carrying with it the bulk of the dirt in the liquid, decanting the resulting coagulant freed liquid from the tank, and distilling the solvent from the decanted liquid to leave an oil substantially free from dirt.

3. The process of continuously recovering oil and solvent from the liquid with its contained oil, fatty matter and dirt resulting from a continuous treatment of wool with a volatile chlorinated hydrocarbon solvent which consists in continuously discharging the said liquid into a tank and mixing therewith an alkaline liquid substantially anhydrous, non-soluble in, and of lower specific gravity than the solvent to effect partial saponification of the fats contained in the liquid and to coagulate the dirt and fatty matter, and, after the coagulant mass thus formed has floated to the top carrying with it the bulk of the dirt in the liquid, continuously decanting the resulting coagulant freed liquid from the tank, periodically drawing oiT from the tank the floating coagulant mass and any sludge settling to the bottom, and distilling the solvent from the decanted liquid to leave an oil substantially free from dirt. V

4. The process of continuously recovering oil and solvent from the liquid with its contained oil, fatty matter and dirt resulting from a continuous treatment of wool with a solvent of the group consisting of trichlorethylene and perchlorethylene which consists in continuously discharging the said liquid into a tank and mixing therewith triethanolamine to effect partial saponification of the fats contained in the liquid and to coagulate the dirt and fatty matter, and, after the coagulant mass thus formed has floated to the top carrying wih it the bulk of the dirt in the liquid, continuously decanting the resulting coagulant freed liquid from the tank, periodically drawing off from the tank the floating coagulant mass and any sludge settling to the bottom, and distilling the solvent from the decanted liquid to leave an oil substantially free from dirt.

ROLAND E. DERBY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,097,147 Dinley Oct. 26, 1937 2,279,408 McDonald Apr. 14, 1942 2,352,365 Booth June 2'7, 1944 2,373,646 Binnington Apr. 1'7, 1945 2,447,845 Dinley Aug. 24, 1948 

1. THE PROCESS FOR RECOVERING OIL AND SOLVENT FROM THE LIQUID OBTAINED FROM THE CLEANING AND SCOURING OF WOOL WITH VOLATILE CHLORINATED HYDROCARBON SOLVENT WHICH CONSISTS IN MIXING THE SAID OBTAINED LIQUID WITH ITS CONTAINED OIL FATTY, MATTER AND DIRT AND AN ALKALINE SUBSTANTIALLY ANHYDROUS, NON-SOLUBLE IN, AND OF LOWER SPECIFIC GRAVITY THAN THE SOLVENT TO TANK TO EFFECT PARTIAL SPONIFICATION OF THE FATS CONTAINED IN THE LIQUID AND TO COAGULATE THE DIRT AND FATTY MATTER, AND, AFTER THE CONGULANT MASS THUS FORMED HAS FLOATED TO THE TOP CARRYING WITH IT THE BULK 